/*
 * Copyright 2002-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.test.web.servlet.result;

import org.hamcrest.Matcher;
import org.springframework.http.HttpHeaders;
import org.springframework.mock.web.MockHttpServletResponse;
import org.springframework.test.web.servlet.ResultMatcher;

import java.util.Arrays;
import java.util.List;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.springframework.test.util.AssertionErrors.*;

/**
 * Factory for response header assertions.
 *
 * <p>An instance of this class is available via
 * {@link MockMvcResultMatchers#header}.
 *
 * @author Rossen Stoyanchev
 * @author Sam Brannen
 * @author Brian Clozel
 * @since 3.2
 */
public class HeaderResultMatchers {

    /**
     * Protected constructor.
     * See {@link MockMvcResultMatchers#header()}.
     */
    protected HeaderResultMatchers() {
    }


    /**
     * Assert the primary value of the response header with the given Hamcrest
     * String {@code Matcher}.
     */
    public ResultMatcher string(final String name, final Matcher<? super String> matcher) {
        return result -> assertThat("Response header '" + name + "'", result.getResponse().getHeader(name), matcher);
    }

    /**
     * Assert the values of the response header with the given Hamcrest
     * Iterable {@link Matcher}.
     *
     * @since 4.3
     */
    public <T> ResultMatcher stringValues(final String name, final Matcher<Iterable<String>> matcher) {
        return result -> {
            List<String> values = result.getResponse().getHeaders(name);
            assertThat("Response header '" + name + "'", values, matcher);
        };
    }

    /**
     * Assert the primary value of the response header as a String value.
     */
    public ResultMatcher string(final String name, final String value) {
        return result -> assertEquals("Response header '" + name + "'", value, result.getResponse().getHeader(name));
    }

    /**
     * Assert the values of the response header as String values.
     *
     * @since 4.3
     */
    public ResultMatcher stringValues(final String name, final String... values) {
        return result -> {
            List<Object> actual = result.getResponse().getHeaderValues(name);
            assertEquals("Response header '" + name + "'", Arrays.asList(values), actual);
        };
    }

    /**
     * Assert that the named response header exists.
     *
     * @since 5.0.3
     */
    public ResultMatcher exists(final String name) {
        return result -> assertTrue("Response should contain header '" + name + "'",
                result.getResponse().containsHeader(name));
    }

    /**
     * Assert that the named response header does not exist.
     *
     * @since 4.0
     */
    public ResultMatcher doesNotExist(final String name) {
        return result -> assertTrue("Response should not contain header '" + name + "'",
                !result.getResponse().containsHeader(name));
    }

    /**
     * Assert the primary value of the named response header as a {@code long}.
     * <p>The {@link ResultMatcher} returned by this method throws an
     * {@link AssertionError} if the response does not contain the specified
     * header, or if the supplied {@code value} does not match the primary value.
     */
    public ResultMatcher longValue(final String name, final long value) {
        return result -> {
            MockHttpServletResponse response = result.getResponse();
            assertTrue("Response does not contain header '" + name + "'", response.containsHeader(name));
            String headerValue = response.getHeader(name);
            if (headerValue != null) {
                assertEquals("Response header '" + name + "'", value, Long.parseLong(headerValue));
            }
        };
    }

    /**
     * Assert the primary value of the named response header parsed into a date
     * using the preferred date format described in RFC 7231.
     * <p>The {@link ResultMatcher} returned by this method throws an
     * {@link AssertionError} if the response does not contain the specified
     * header, or if the supplied {@code value} does not match the primary value.
     *
     * @see <a href="https://tools.ietf.org/html/rfc7231#section-7.1.1.1">Section 7.1.1.1 of RFC 7231</a>
     * @since 4.2
     */
    public ResultMatcher dateValue(final String name, final long value) {
        return result -> {
            MockHttpServletResponse response = result.getResponse();
            String headerValue = response.getHeader(name);
            assertNotNull("Response does not contain header '" + name + "'", headerValue);

            HttpHeaders headers = new HttpHeaders();
            headers.setDate("expected", value);
            headers.set("actual", headerValue);

            assertEquals("Response header '" + name + "'='" + headerValue + "' " +
                            "does not match expected value '" + headers.getFirst("expected") + "'",
                    headers.getFirstDate("expected"), headers.getFirstDate("actual"));
        };
    }

}
